两株产生大环内酯Macrolactin S的海洋细菌的筛选及鉴定

目的:从中国东海分离筛选抗菌活性微生物,确定活性菌株的分类地位。方法:随机挑选30株本室保存的分离自中国东海的细菌,利用抗大肠杆菌模型进行活性筛选。对活性菌株进行形态特征、生化特征、盐需求测试及16S rDNA序列分析,并将所测得的序列在NCBI数据库进行相似性搜索,选取其中具有代表性的序列以邻接法构建系统进化树,将菌株鉴定到属。结果:筛选出活性菌株F81612和F201721,它们的最适生长盐浓度分别为10%和7.5%,菌株形态特征、生化性质与Bacillus sp.相符,菌株F81612和F201721的16S rDNA序列分别与Bacillus subtilis和Bacillus amyloliquefaciens相似程度最大。结论:利用抗大肠杆菌模型筛选到两株产大环内酯Macrolactin S的细菌,均为中等嗜盐的海洋Bacillus sp.。

Screening and identification of two Macrolactin S-producing bacteria from the sea

Objective:To isolate and screen active marine microorganisms from the East China Sea and to identify the phenotypes of the isolated strains.Methods: Thirty strains of bacteria isolated from the East China Sea were selected randomly,and the active strains were screened out by the anti-Escherichia coli model.The active strains were subjected to physiological and biochemical characteristics,salt-aggregation test,and 16S rDNA sequence analysis.Neighbor-joining trees were constructed by comparing the results of 16S rDNA sequences with sequences described in the BLAST server of the National Center for Biotechnology Information (NCBI); the strains were subsequently identified to genus level.Results: Strains F81612 and F201721 were screened out with the optimum salinities of 10% and 7.5%,respectively.Their morphology and biochemical characteristics were similar to those of Bacillus sp..16S rDNA sequence analysis showed that sequences of F81612 had a higher similarity to those of Bacillus subtilis; F201721 was similar to Bacillus amyloliquefaciens.Conclusion: Two Macrolactin S-producing strains have been screened out by the anti-Escherichia coli model,and they are identified as moderate halophilic Bacillus sp.